Biostar |
februari 17, 2000 |
They're all based around one basic chipset: the 82c3491 or 82c491. The 3491 is a later version of the 491.
Now, the part number: MB-1425/33/40/50UCV-A
MB-14 is generic. Means "motherboard" :-)
25/33/40/50 means clock speed. Early boards came with fixed
frequency crystal, and the number represented which crystal was fitted. Later boards
came with jumper-selectable frequency, thus they had all speeds listed in part numbers.
later still, the speed-list was abbreviated to just 1433/50
for abbreviation purposes only. UCV is the 'real' model number. The -A is the revision.
-A boards support 4x30 pin SIMM only
-B,-C&-D board support 4x30 and 2x72 pin SIMM's, however the manufacturer may fit the
bare board with 8x30 pin sockets if he wants to..
-D and later support green fuction (with new k/b controller chip)
-E boards MIGHT support 3.3v CPU series (if manufacturer put the regulator onboard)
so.. basically, -A boards have their own BIOS
-B & -C boards have their own (interchangeable) BIOS
-D & -E boards have their own (interchangeable) BIOS
The -E BIOS 'knows' more CPU's, and the cpu type status displayed onscreen therefore is
accurate with, say, cyrix CPU's, whilst the -D BIOS isn't.
The boards don't support anything higher than intel dx4-100, amd dx4-100, cyrix dx4-100.
there is no support for cyrix 5x86-100/120, amd 5x86-133/160.
The board DOES support intel P24T Pentium Overdrive, however.
Other rules: If board has '491' chipset, do not use bios from '3491'
or vice-versa - they're not software-wise the same. usually only -A boards have 491 chip,
others have 3491.
only AMI bios used, never award, etc. AMI bios always pre-LBA text mode setup type BIOS,
never GUI type, never LBA, never APM.
There are no known 'bugs' in any version of BIOS, only changes to work with hardware
modifications.
Thanks to Craig Hart for this information.
On the MB-8500TAC by "th"
There are at least 6 Rev, but these Revs are not reflected by
the 6 Rev. that quantex has. I have two TAC, one Rev 5 and one Rev 6, but both are P5ZB.
Quantex has different names for different manufacture options. Biostar itself divides the
TAC into two categories: Rev 1-3 and Rev 4-6
ATM it looks like this:
There are only 2 Bios-versions, one for SMC-I/O and one for UMC-I/O.
Dated June 2, 1998 (Featuring CD/LS-Boot and hdd > 2GB)
The Taiwan ftp-server has a more recent UMC-version (July 20, 1998)
which supports Overdive-procs, but no SMC-version
Here is a Quantex <-> Biostar comparison
P5CB: UMC, Async Cache, earlier Revs (1-3)
P5MB: UMC, Sync Cache, earlier Revs (1-3)
P5RB: SMC, Async Cache, Rev ?, I/R ?
P5SB: SMC, Sync Cache, Rev ?, I/R ?
P5YB: UMC, Async Cache, later Revs (4-6)
P5ZB: UMC, Sync Cache, later Revs (4-6)
Later Revs usually support more CPUs. It seems that Rev 1 supports Pentium only whereas
Rev 6 supports AMD K5, Cyrix 6x86 (some), Pentium and Pentium MMX! The SMC boards do only
have the internal mouse-port not the external.
I wrote to you that 8500TAC Rev. 6 supports intel MMX. Official statement is, that it does not, but Rev 6 supports split voltage with 2.8V/3.4V. Board Rev 4 and 5 are 2.5V/3.4V. IMHO: Don't try to use the K6/III in this board (because of the 2.5V). The power plane is not strong enough for this CPU. Another problem is the speed, because the pull-up/pull-down issue for BF0 and MMX. Therefore the speed may be limited to 166MHz (2.5 x 66)."
Wanted BIOSs:
© 1996-2001 Wim Bervoets, Contact Information
DISCLAIMER: Use flash BIOSs at your OWN risk!! I can not be held responsible for any damage to your computer !